The present invention relates, in general, to a method and apparatus for harvesting sod, and more particularly to a system for cutting sod into a plurality of side-by-side strips, cutting the strips transversely into predetermined lengths, or blocks, conveying the side-by-side blocks to the top of an automatic stacker, and periodically operating the stacker to deposit the blocks in corresponding stacks on a pallet.
The art of harvesting sod is well-developed, and numerous machines have been developed for this purpose. Typically, a sod harvesting machine includes a reciprocating or vibrating cutting bar which has a bottom horizontal blade designed to sever the sod from the ground at a selected depth, and two vertical side blades, one at each end of the horizontal blade, to cut the sod in a strip of the desired width. Such cutter bars are generally mounted on a suitable frame and are driven by a mechanical drive mechanism so that as the frame is advanced the bar reciprocates to undercut the sod. As illustrated in the copending application Ser. No. 314,310 of Martin Beck, filed Dec. 12, 1972 and entitled "Ganged Sod Harvesting Apparatus", such a sod cutting mechanism may incorporate three cutting bars operable to produce three adjacent strips of sod.
The major problem encountered in sod harvesting systems, however, is in the handling of the sod strips after they have been cut. Conventionally, the strips of sod are cut into predetermined lengths by periodically downwardly driving a transverse cutting blade. These lengths of sod are picked up by an attendant following the harvesting machine, formed into a roll or folded in half, and manually stacked on a pallet for transportation to the place of use. Not only is this procedure inefficient and time-consuming, but the rising costs of labor dictate that it be automated to the greatest possible extent.
Various machines and methods have been developed to carry out this stacking procedure automatically. For example, a machine has been developed which automatically picks up the cut lengths of sod and rolls them into a bundle. An attendant standing behind the end of the conveyor-roller machine lifts each bundle off the conveyor and deposits it on a pallet which may be carried by a fork-lift device. Although this reduces the time and work involved in forming rolls of sod, it still requires the presence of an attandant to lift and stack each roll, and thus does not overcome the labor problem of the prior art. In copending application Ser. No. 57,930 of Martin Beck, filed July 24, 1970 and entitled "Method and Apparatus for Sod Harvesting and Laying", a method and apparatus for rolling previously cut strips of sod onto a reel is disclosed, thereby eliminating the need for an attendant to manually lift each block of sod as it is cut. Various other machines for forming and stacking rolls of sod are known in the art. However, these prior devices do not take into account the fact that some types of sod cannot conveniently be formed into rolls, and further do not take into account the fact that many customers who purchase sod prefer to purchase it in an unrolled condition. Accordingly, there is a real need in the sod-harvesting art for a machine for automatically picking up strips of sod and stacking them on a pallet without the need for manual rolling, lifting, or other handling by an attendant. The present invention provides such a machine.